Solenoids of this type are known in a large range in technology. The movement of the armature is used for triggering very different elements, for example, solenoids are used for triggering valve elements. Solenoids are expected to have a long service life, that means they are supposed to outlast a number of switching processes reliably and with a quality as constant as possible and that they are accordingly reliable.
For example, the armature is held by a suitable pull-back spring in unelectrified condition of the solenoid in a final position. If now the power winding is loaded with current, the magnetic field forms in the interior of the coil, in particular in the armature space, and acts on the armature which then is accelerated rather fast and bounces against the pole core. The result is a certain wear which leads during a number of switches (for example 10 million, 15 million or 20 million switches) to a considerably changed switch behaviour of the solenoid. It has been observed that ruptures on the armature have been the result of the high bouncing energy and this has reduced the quality of running of the armature which leads to corresponding conspicuous behaviour during the drop-out of the armature.